Small water tight box

Could some kind person offer some advice about making a small water tight box? Mad or not, I am attempting to convert a Hobby Boss 1/350 scale USS Virginia sub to a dynamic diving RC sub. There seem to be a fair few RC components available on Ebay which are small enough to achieve this and fit into a hull that is about 3cms in diameter and 32 cms long. I think it would have to be a box rather than a cylinder and I have lots of plasticard to make one or more. I'd use fine diameter brass tube and fine brass rod for the servo rods and prop shaft. I presume these need greasing or oiling first to make them watertight? I think I'd add a brass prop. I'm used to modelling in very small scales so that side of things doesn't worry me!

Cheers
Simon

Or is there somewhere I could buy some thin (to allow maximum space for the bits and pieces) clear plastic tubing around this diameter (around 2.9cms) and if so, how would I make waterproof end caps with waterproof exit holes for the brass tubes? Thinking about it, I could make my own cylinder by rolling thin plasticard and using Mek solvent along the seam and make end caps from thicker plastic sheet.

Apart from the WTC could someone advise me on the RC side of things? I need to know what voltages (throughout), frequency for receiver and crystals and whether to go for a brushed or brushless motor. I live in France by the way so this might affect the acceptable frequency.

Many thanks
Simon

That's great Richard; many thanks for the advice and the info about components. I've decided to make my own wtc and see how I get on with it, and so far I've made up some end caps which are a snug fit inside the hull. If I have some success with the conversion I might post a short build thread on here in case any others would like to have a go.

All the best
Simon

I'd really agree with Richard - go for a piece of plastic pipe as the basis of the WTC and Plasticard is a bit flimsy for underwater use.
Pushrod seals - bellows or a sliding piece of silicone rubber tube.(Nigel likes the latter,I think.)
In most model shops you can get brass tubes that fit closely one within an other - very useful things.

David

Hello Richard and David,

The problem is finding clear tubing (preferably) that is sufficiently thin to give the maximum room inside for the RC bits and pieces as the outside diameter can't excede 2.7 cms! I've been experimenting with some spring water bottle clear plastic, rolled to make a tube of this diameter and have made it fit snugly inside the hull. The problem with this are the ends caps or seals. Obviously the tube has flex in it unlike perspex or something similar so it has to be handled carefully. If I could just make a water tight cylinder I know I could get this submarine to work. I don't suppose anyone could make a WTC like this with proper end caps and O rings?

I don't envisage the submarine going very deep; more sub surface, surface running.

You're right Richard! It may just be a wee bit too small to get an effective water tight something in. If I used plastic tubing of the right diameter it would probably be too thick walled. I wouldn't go down this route at all if I could either buy a used working submarine or a reasonably priced kit. Money really is tight. I still quite like the idea of the MMB Los Angeles semi kit. Other alternatives are Matt Thor's Permit (available again in June) or the Caswell Revell Skipjack conversion kit. If I could just buy a rtr sub that would suit me the most as I have no experience in the field.

Cheers
Simon